Hi Way2Tired,
I tend to suggest treating the purchase of an adjustable bed as more of a “commodity purchase” based on price per features comparisons so if the Prodigy you purchased includes all the features that are most important to you and the cost was less than other adjustable beds you were considering that have the same features (regardless of any additional features that you don’t end up using) then it would be the “best” choice for you. There is more about choosing an adjustable bed in post #3 here and the adjustable bed thread that it links to.
Many of your mattress questions are very subjective and the answers are relative and would vary depending on each person’s criteria so I can certainly make a few comments or give you some suggestions about “how” to choose but you will need to decide on the risks involved in each of the choices you are considering based on your knowledge of your own circumstances and history.
I think that the two posts that will be most helpful with your decisions are post #2 here which has more information about the different ways to choose a mattress and how to assess and minimize the risks involved in each of them and post #13 here which has more information about the most important parts of the “value” of a mattress purchase that can help you make more meaningful comparisons between mattresses.
Every layer and component in a mattress will affect the feel and performance of every other layer to some degree so every difference between two mattresses in any of the layers or components will make a difference in how the two mattresses compare … not just the top layer. Having said that though … the top 3" to 6" or so will probably make the biggest difference in how two mattresses “feel” for most people when they lie on them although the deeper layers can have an effect on how you feel when you wake up in the morning because they can have a significant effect on your alignment.
The Beautiful has a top 3" layer of 15 ILD and then a 3" layer of 24 ILD underneath this and has a stretch knit cover. The 13" SleepEZ would be the closest comparison (thickness can also affect how soft a mattress feels) and with two soft layers on top would have 6" of 19 ILD and has a wool quilted cover (see post #6 here for more about wool quilted covers). Most people would feel a difference between 15 ILD and 19 ILD and in combination with the stretch cover the Beautiful would likely feel noticeably softer for most people but “how much” softer it would feel for any specific person can only be answered based on their own personal experience.
This depends entirely on your confidence that a mattress you are considering will be a suitable match for you in terms of PPP. If you are 100% confident that your testing in the store will reliably predict your actual sleeping experience and there is no possibility of making a mistake that would have a meaningful effect on your sleeping experience then there would be little benefit to a comfort exchange and you would probably be better off with the lower cost (comfort exchanges are built into the cost of a mattress and the people who don’t exchange a mattress pay for the ones that do). On the other hand if you aren’t certain at all or if you end up purchasing a mattress that isn’t as suitable for you in terms of PPP as you hoped for then an exchange policy can have a significant effect on the risk of a mattress purchase. Most people are somewhere in between these two tradeoffs (risk vs cost) and need to decide on the risk involved in their purchase and their risk tolerance and the options they would have available if they make a “mistake” in their choice to decide which of these tradeoffs is most important to them.
Latex is very “sticky” and doesn’t tend to shift inside a mattress with a suitable tight fitting cover so there would be little risk of layers shifting but if for some reason they do then with a zip cover it’s a simple matter to unzip the cover and “wave” them back into position again. There is more about the pros and cons of each in post #2 here and the posts it links to.
There would be “little” difference between Talalay GL and “regular” talalay if they were the same ILD. Some people have said that the Talalay GL can feel a little “stiffer” to them although they may have been feeling more of the ILD difference between two layers that they were comparing than the difference in the material itself.
Again this would depend on your own risk tolerance. All softer materials will be less durable than firmer materials of the same type. Warranties only cover defects in a material not the loss of comfort and support and actual defects in a material tend to show up early in the life of a mattress. Outside of actual defects in a material (which aren’t common) … the tradeoff here would be about suitability vs durability and sleeping well for a shorter period of time before you may need to replace a layer (or the mattress) or sleeping less well (if the materials are slightly too firm) but for a longer period of time. I personally believe that PPP is the most important part of the “value” of a mattress purchase and I would personally rather sleep better for a shorter time than not sleep as well for a longer period of time … especially if individual layers can be replaced.
Hopefully this has helped you to clarify the risks and benefits involved with each of your choices so you are in a better position to make a final choice between them (see post #2 here).
Phoenix